1. Field of the Invention
This invention relates to endotracheal tubes of the permanently curved, plastic, disposable type. More particularly, it relates to such endo tubes designed to permit nasal intubation to be accomplished easily and without patient trauma.
2. Description of the Prior Art
Endotracheal tubes of the curved plastic disposable type have been commercially available for some years. At first such endo tubes were made with inflation tubes for balloon cuffs on the outside of the tubes or positioned within a single lumen in the tube. More recently improved endo tubes with unobstructed primary lumen having a secondary inflation lumen totally within the wall of the tube have been developed (see U.S. Pat. No. 3,615,793; 3,633,586; 3,725,522 and 3,755,525).
Nasal intubation with an endotracheal tube is a difficult procedure due to the anatomical configuration. The anesthesioligist must use a tube of proper size to fully supply the needs of the patient. This happens to be the largest tube the patient can pass. Human anatomy is such that the tube enters and advances until it reaches the back part of the nasal passage where the direction changes and the passage narrows. The tube tip invariably pokes into the back of the passage and resists turning the corner which leads toward the trachea. The tubes are curved and the anesthesioligist might use a lubricant, but neither of these insures easy passage.
Flexible metal probes or catheters have been provided with control cables for the purpose of guiding the probes or catheters around corners or bends in the body of a patient during installation of the probe or catheter (See U.S. Pat. No. 2,574,840). Intubating stylets have also been used to assist the curving of endotracheal tubes within the body of a patient during intubation (See U.S. Pat. Nos. 2,463,149 and 2,541,402).
Notwithstanding various improvements and developments in medico-surgical tubes, including endotracheal tubes, as mentioned above, there is a need to provide improvements in endotracheal tubes, particularly those used for nasal intubation, to permit easier and less traumatic introduction into the patient. Especially, there is a need for improved endotracheal tubes which will provide a maximum of bending control during intubation for advancing the tube around the corner at the back of the nasal passage in which this is accomplished without introducing detriments, e.g., partial blockage of the major lumen of the tube, destruction of full integrity of the major lumen of the tube or the like.